Sex differences have been observed in the pressor response to norepinephrine and ADP induced platelet aggregability. The responses were greater in the male than the female. Moreover, these effects appeared to be androgen dependent. The purpose of this study is to confirm and extend these observations. The data will initiate a novel approach to drug therapy in cardiovascular disease. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress reports if a grant is awarded as the result of this application.